This invention relates to a steam separating apparatus and, more particularly, to an apparatus for receiving a mixture of liquid and vapor and separating the liquid from the vapor.
In natural circulation vapor generators, mixtures of water and steam rise in heated steam-generating tubes and discharge into one or more large steam drums disposed in an elevated position above the tubes. The drums include means to separate the water from the steam with the latter being removed through openings in the upper portions of the drum and the former being recirculated through downcomers to the boiler and back to the steam generating tubes to complete the natural circulation loop.
In relatively large installations employing natural circulation vapor generators, it is essential that an efficient separation of the steam from the water be effected in the drum with minimal pressure loss in order to furnish steam of the required purity to the point of use, and steam-free water to the circulation system. To this end, many previous arrangements have used separators having spiral arms which discharge the steam-water mixture tangentially towards the inner wall of a shell, or skirt, to promote the separation. Although satisfactory for most purposes, this type of arrangement, even if combined with another drying stage, does not insure maximum separation and is therefore less than completely desirable for more stringent applications.